CD47 is a cell surface receptor comprised of an extracellular IgV set domain, a 5 transmembrane domain, and a cytoplasmic tail that is alternatively spliced. Two ligands bind CD47: signal inhibitory receptor protein α (SIRPα) and thrombospondin-1 (TSP1). CD47 expression and/or activity have been implicated in a number of diseases and disorders. Accordingly, there exists a need for therapeutic compositions and methods for treating diseases and conditions associated with CD47 in humans and animals, including the prevention and treatment of solid and hematological cancers, ischemia-reperfusion injury (IRI), cardiovascular diseases, or an autoimmune or inflammatory disease. There also exists a need for diagnostic compositions and methods for determining the level of CD47 expression in tumor samples.